With the advent of semiconductor devices having increasingly large component densities, the removal of heat generated by the devices has become an increasingly challenging technical issue. In the past, the low power dissipation of most chips accommodated the use of low cost, air-cooled or and liquid-convection heat sinks. However, many modern higher power-dissipation semiconductor chips now require substantially greater heat dissipation than heat sinks can reasonably provide.
A number of cooling methods currently exist that can provide high heat transfer rates that are desirable for cooling the higher-dissipation devices. Some of the more efficient cooling methods are the direct-fluid cooling methods, such as micro-channel cooling, spray-cooling, and jet impingement cooling, wherein a cooling fluid is introduced directly on the device to cool off the device. A direct-fluid method typically involves multi-phase cooling, because it involves a transformation of an amount of the applying cooling fluid from a liquid phase to a vapor/gas phase once it absorbs the heat generated from the applied device.
Thermal management of heat-generating devices involves a stable balance between the heat flux in such devices and the heat dissipated by the cooling mechanism, such as cooling fluid. Although multi-phase cooling provides high heat transfer rates, they are unstable at such high rates. That is because such high heat dissipation rates cannot be sustained for long periods of time due to an onset of unstable equilibrium. This is especially true for direct-phase cooling, such as direct-fluid cooling wherein the phase-changing fluid is applied directly to the surface of heat-generating devices and thus highly dependent on surface conditions of such devices. Thus, such a cooling method is forced to operate at lower performance to provide stability.
Accordingly, it is beneficial to have the ability to properly manage a direct-phase cooling method, such as a direct-fluid cooling method, for high heat dissipation in a heat-generating device so as to provide optimum performance and surface thermal conditions for such a device.